docs: def raise_on_wrong_settings(self):
          """
          Validates the configuration settings and raises RuntimeError on error
          """
          self.__ensure_dir_exists(self.working_directory, 'working directory')
          for idir in self.include_paths:
              self.__ensure_dir_exists(idir, 'include directory')
          if self.__xml_generator not in ["castxml", "gccxml"]:
              msg = ('xml_generator("%s") should either be ' +
                     '"castxml" or "gccxml".') % self.xml_generator
              raise RuntimeError(msg)